Milling apparatus for grains and other materials



H. A. NOLL July 26, 1955 MILLING APPARATUS FOR GRAINS AND OTHERMATERIALS Filed DEC- 29, 1950 3 Sheets-Sheet l 7 r a Z8 A 3 1 3 m J a av 7 j A 2 W13 7 WI Hi 7 r m Q. 3 a 8 5 V 5 3 2B 3 a A \H 7 Z x c 3 & 19.Nail.

5 Sheets-Sheet 2 H. A. NOLL Z rzd erziafl in r July 26, 1955 MILLINGAPPARATUS FOR GRAINS AND OTHER MATERIALS Filed Dec- 29, 1950 July 26,1955 H. A. ou.

MILLING APPARATUS FOR GRAINS AND OTHER MATERIALS 5 Sheets-Sheet 3 FiledDec. 29, 1950 United States Patent ()fiice 2,753,937 Patented July 2 5,1955 MlLLING APPARATUS iron; GRAINS AND oTHEn MATERIALS Heinrich A.Noll, Dusseldorf, Germany, assignor to H. H.

and H. Manufacturing Co., Chicago, Ill., a corporation of IllinoisApplication December 29, 1950, Serial No. 203,491 6 Claims (Cl. 24179)This invention relates to milling methods and apparatus particularlyadapted for producing flour from grains, especially wheat, but also ofvalue in the grading and selective separation'of other materialsincluding dyestuffs.

In the interests of convenience and simplification of disclosure, theprocessingflthe apparatuses and the system .1

separating and purifying units employ a number ofscreens zor sieves ofdifferent mesh fineness which are agitated or vibrated in variousmanners and by suitable mechanisms to effect selective separations. Suchsieving or screening devices, commonly known as plane sifters, are

expensive to manufacture, to install and to operate and theirmaintenance costs are relatively high. Furthermore the vibratingsifters, when loaded, are very heavy indeed and when agitated orvibrated, frequently shake their supporting structures including thebuildings in which they are housed. Usually also it is necessary to aidthe sifting or screening operation by employing brushes, wipers orscrapers to move over the screen or sieve surfaces to force theparticles of ground material through the mesh openings in the screen orsieve as well as to clear away those particles of a size too large to beforced through the mesh openings, the result being that the sieve orscreen material is soon worn out therefore requiring frequentreplacement. In addition such prior art apparatuses require extensivefloor space and substantial supporting structures, all of which is tosay that the magnitude of the equipment and structures required and theexpense entailed makes it difficult if not impossible for the smalloperator to enter the business especially if his operations and marketare morelor less localized and restricted.

Plane sitters and present day operating methods connected therewithinvolve a number of other disadvantages, Where, for, instance, a mill isdesigned to produce a high capacity of. finely ground material such ascereal flour, itis necessaryto provide a tremendous or what may be saidto be an apparently disproportionate number of plane sifters,centrifugal separators and related apparatuses relative to the grindingor crushing machinery capacity and the product quantity produced.Moreover,

clogging of a screen may require a shut-down of the mill or of thesifter at least, with consequent losses, and when the number of planesifters and screens increases, the number of such delays and the totalloss becomes extrern ely serious,

The main objects of this invention, therefore, are to provide animproved method, system and sifting or separating apparatus for securingthe sequence ofoperations essential "to extract from ground materialssuch, for

instance, wheat, those finely cornminuted particles of predeterminedsizes which may be required for a marketable product of high and uniformgrade; to provide an improved sifting method, system and apparatus whichutilizes suction not only to convey the ground grain or other materialfrom a grinder or crusher to the sifters and separating units but alsoto effect all or substantially all of the sifting, separating andpurifying steps to produce flour and intermediate products from thecomminuted grain; to provide an improved method, system and apparatus ofthis kind requiring no agitating or vibrating machinery for the screensor sieves and having a minimum of parts, hence capable of beinginexpensively manufactured and economically maintained while susceptibleof various adaptations so as to be especially available to the smallflour producing operator; and to provide equipment of this kind havingan improved arrangement of screen sieves and a pump or blower and acollector with conduits connecting these pieces of apparatus wherebythere may be a continuous flow of material into the grinder and fromthe. grinder discharge on through the various apparatuses which effectseparation of the various grades or sizes of the ground particles anddelivery of them to suitable places for collection.

Fig. 2 is a sectional view in elevation of a preferred form of separatoror sieving device which may be employed in carrying out this invention;Fig. 3 is a transverse sectional view of the apparatus shown in Fig. 2,the view being taken substantially along the section line 33 of Fig. 2;

Fig. 4 is a sectional view in elevation of a modified form of separatoror sieving device which may be used in carrying out this invention;

'Fig. 5 is a sectional view in elevation of another modified form ofseparator or sieving device;

Fig.6 is a transverse sectional view of the latter taken on the line 6-6of Fig. 5;

Fig. 7 is a sectional view in elevation of still another modified formof separator;

Fig. 8 is a sectional view in elevation of the separator of Fig. 7, theview being taken on the line 88- of Fig. 7; and i Fig. 9 is an enlarged,fragmentary detail showing, as respects the modified form of separatorshown in Fig. 7, the manner in which the screen fabricmay be stretchedand held in place on a rotating ring. One of the principal features ofthe invention, broadly speaking, involves the employment of differentialpressures to eifect the movement of materials from the time they areground to the end of the separating or sieving and settling orcollecting steps in a milling process. However, it is to be understoodthat the expression differenti'al pressure as used herein is intended toinclude the creation or tendency toward creation of a lesser pressure ata definite place or places within the system by positive means, such asa pump, causing or tending to cause a pulling or drawing or suctioneffect to be applied to the air or other gas or fluid and the materialsentrained therein and carried thereby within the system or some partthereof, as distinguished from a mere pushing" or pressing force alonedriving or tending to drive the material and its fluid carrier into orthrough the systern or some part thereof. it should also be understood,of course, that a combination of pulling and pushing forces i. e.differential pressure created by both a force pump action and a suctionpump action, is within the intended meaning of the expression as usedherein. In the illustrated embodiments of the invention one or moresuction pumps or blowers in the system serve alone or with the additionof such positive pressure as may be created by other means, as, forinstance, a force pump, or a grinder of the type disclosed in my PatentNo. 2,651,471, dated September 8, 1953, to pull or draw the groundmaterial from a grinder or crusher and through all of the systemincluding sieves or sitters and to and including a centrifugalseparator.

In the illustrative embodiment of Fig. 1, there is a rinder or crusher Awhich may be of the type disclosed in my said patent, a separator orsievin apparatus B, a centrifugal separator or settling chamber C, apump or blower D, and a collector E. The grinder, the separator and thepump or blower have moving parts which are driven by or from anysuitable source of power. Materials ground in the grinder A aredischarged therefrom into a conduit 11 in which there may be a sightglass 12 for inspection purposes and which leads to the inlet 13 of theseparator or sieving apparatus B. Material passing through the sievingapparatus B flows through the outlet 13' into a conduit 14 which carriesit into the centrifugal separator C which may be of any usualconstruction, where those heavier and coarser particles which havepassed the sieves or shifter screens in separator B, are deposited andremoved by the combined effects of centrifugal force and gravity whilethe lighter and finer particles are carried on through a conduit 15 tothe pump or blower D and thence are forced through conduit 16 into afilter bag or other collector E. All or a major part of the forcerequired to effect the transportation of the ground material as well asits separation into selected parts may be supplied by the pump or blowerD but such force may be supplemented, if desired, by the fanning orblower effect of a grinder, such as that of said Patent No. 2,651,471,or by the introduction of another pump or blower in the system betweenthe separator or sieving apparatus B and the collector orfilter-collector E as, for instance, in the conduit 14.

The separator or sieving apparatus B comprises a housing or vesselhaving relatively cylindrical side walls 17 and its axis extending in avertical direction, a conical cap 18 closing its top and effectingconnection with the conduit 11, a conical bottom cap 18' closing itsbottom end and etfecting connection with the conduit 14, a plurality orseries of non-vibrating or non-vibratory sieves or screens generallydesignated 19, a set of vanes, sweeps or the like generally designated21 which may carry or represent scrapers, wipers, brushes or the like,and mechanism, including shafts 22, 23, gearing 24 and a pulley or otherdevice 25', whereby power may be transmitted to rotate either thescreens 19 or the vanes 21. The shaft 22 may be mounted in suitablebearings, thrust and radial 26, 27, carried by spider supports 28, 29secured in the housing. The shaft 23 may be supported in bearings 31, 32carried by a housing 33 which may also shield the shaft and gearing frommaterial entering the top of the separator.

Preferably, the sieves or screens 19 are successively of smaller orfiner mesh from top to bottom so that all but the largest or most coarseparticles of material may pass the top screen or sieve, eachsuccessively lower screen passing smaller or finer particles than thescreen immediately thereabove and retaining particles too large orcoarse to pass. In order to prevent accumulations of coarse ornon-passing material particles from retarding or blocking the flow ofother particles susceptible of passing the screens and to move suchcoarse particles in each grade of particle size from the upper surfacesof the screens for further grinding or other purposes, the sepachutestructure.

rator is equipped with a series of chutes diagrammatically illustratedat 34 in Fig. 1 and designated 34 in Fig. 2 since they representsomewhat different arrangements. The separator of each of Figs. 1 and 2employs rotary sweeps or vanes, rotation thereof being effected by theshaft 22 to which they are attached, while the screens are suitablysecured to the housing against movements relative thereto but are cutaway over the chutes to permit the sweeps or vanes 21 to move or sweepthe coarse screenings into the chutes as will be understood.

Chutes 34 (Fig. 1) are illustrated as connected with and emptying into aseries of bins, compartments or the like 35. Valves in these bins orcompartments (a valve stem 36 in Fig. l symbolizing such valves) controlthe flow of material particles therefrom into conduits 37 which join ata header 38 the flow from which into a single discharge conduit 39 mayalso be controlled by a valve. Preferably, the valves in the bins 35 areselectively operable so that material particles may be releasedindividually or in any desired combination and proportions with materialparticles from any other bin or bins. Some or all of the materialcollected in bins 35 may be returned to the grinder or other dispositionmay be made of it.

The discharge chutes 34' illustrated in Fig. 2 provide for directdischarge of material screenings swept from the top of the screens butbecause the system is under low pressure by reason of pump D, it isnecessary to prevent air from entering the system and to that end eachchute is equipped with a pair of valves 41 hinged at 42 to theAccumulation of a given weight of material behind the valves 41 willcause the valves to open outwardly to permit such material to flow outof the chutes into bags or other receptacles. Valves 41, being sodisposed and mounted, are readily closed by gravity and pressure of airtrying to enter, thereby elfectively cutting off the fiow of air intothe system through the chutes while permitting the relatively free flowof material out of the chutes. As will be appreciated, spring oradjustable weight means may also be employed to close the valves or tosupplement the action of gravity and air pressure; means for opening andclosing these valves by hand may also be employed.

Screenings may accumulate behind the innermost valve 41 until theirweight is suflicient to overcome the forces holding such valve closedwhereupon the valve may open and permit the screenings to flow in behindthe outermost valve which is in closed position to prevent the entry ofair. After a predetermined quantity of screenings has flowed from behindthe inner valve to relieve the pressure it will close or tend to close.However, if the inner valve has not closed at the time the outer valveis pressed open by the weight of material accumulated behind it and thematerial is discharged, the inner valve will be closed by the pressureof the outside air.

As shown in Fig. 2, it may be desirable to equip the vanes or sweeps 21with brushes 43 or other devices to make contact with the upper surfacesof the screens or to approach close to the screen surfaces in order toclear away the screenings so that the suction created by the pump orblower D may be fully effective to draw the finer material through thescreens. It may also be desirable to be able to observe operationswithin the separator and to have access to each screen section therein.To that end the housing may be provided with glassed doors or windows 44and the interior may be lighted by electric lamps 45. In order to effectremoval and replacement of screens and sweeps or vanes as well as forother purposes, the housing or casing 17 may be made with hingedquadrants 46 and 47 normally latched tightly together by fasteningmechanisms such as indicated at 48 in Fig. 3.

While the separators or sifters of Figs. 1 and 2 show fixed screens androtating sweeps or vanes, the modified types of Figs. 4 and 7 employrotating screens, the type of Fig. 4 employing a stationary or fixedvane or a plurality thereof, one vane being shown each of the screen;ing compartments just above the s ho wing Qffth ChlllZC for, such cpmpartmen t, the construction and arrangement being otherwise similar tothose above described. The type of Fig. 7 is designed for horizontalinstead of vertical flow of the material stream. Referring moreparticularly to Figs. 7, 8 and'9, a housing or casingj4l of, generallycylindrical, shape with its axis' herizontal carries a plurality ofpairs of spaced g me e; between. each pair of hich s wate cre n or s evifi man e at sj' on a driven shaft and at its circumferential edge inclamp rings S L Suitablyeuppor tedin theupper portion of each except thelast of the compartments formed by the rotaryjscreens 53 isa cone-shapednozzle 55, each nozzle, being inlaxiallline with the others and, inturn,in. line. with an inl et conduit 56 and an. outlet conduit 57. Thelowersidev of eachcompartrr ent opens into a chute or bin58 which rnay b eval ved" at itsbottorn endfor. removal of screenings accumulatingtherein. The shaftf50, of course, is driven from any suitable source ofpower, the pulley.59, being representative of a power transmittingmeans. 7

The type of separator illustrated in Figs. 5 and 6 varies from the.othersprimarily in having. a housing or. casing 61 of rectangular.cross-section as viewed in Fig. 6 and in having a series of brushes,sweeps or wipers 62 extending transversely. of. an endless belt 63carried over suitable rollers 64.mounted in the housing-above eachscreen or sieve 65, one of each pair of rollers being driven bysuitable. transmission mechanism 67-from a source (Sf-power.

The centrifugal separator C maybe of anyusualtype well known on themarketand so may be the pump or blower D and collector The separator Cmay have a valved outlet- 7-1- at its bottom end and, similarly thecollector E may have a valved outlet 81 Preferably the conduits Hand'14-will be of relatively small diameter to provide a high velocityand low pressure to carry the particles of material flowing therethroughwhile the conduits 1 5 and 16 will be of substantially larger diameterto decrease the velocity with a consequent increase in pressure aswillbe understood; The collector B will be constructed afterthe mannerof the usual vacuum cleaner bags to retain the very fine flour dustwhilepermitting the entrainedair to escape.

The operation of the system, so far as the conveyance of the groundgrain or other material and the sieving or sifting in the screenseparators are concerned, is sub stantially the same regardless of whichtype of separator is employed. If grain is the material to be made intoa flour state, it is ground in the grinder or crusher A and dischargedinto the conduit 11 through which it is drawn by the suction created bythe pump or blower D. The fluid stream of grain particles of varyingdegrees of fineness or size flows into the screen or sieve separator andonto the first sieve or screen which retains only the most coarseparticles and passes all others, the suction or differential pressurecreated by the pull of the pump or blower D, being efiective to performthis separation rapidly and efliciently. The coarse particles retainedby the first screen are removed by the sweeps or brushes, which may beoperated continuously, and are delivered into the top chute. Of thoseparticles which pass the top screen or sieve, the most coarse areretained on the top or upstream surface of the next and finer meshscreen or sieve and are similarly discharged into the chute provided toreceive them, while all finer particles pass on to the next sieve orscreen the mesh of which is still finer than the previous one where theprocess of separation of a coarse grade from all finer grades iseflected in a similar manner.

Those particles which pass the lowest screen or sieve, in the separatorsof the types shown other than that of Figs. 7 and 8, are drawn throughconduit 14 and enter the centrifugal separator C at relatively highvelocity.

Entering separator Cat the perimeter and in a tangential direction, thestream of air with entrained particles whirls around, the heavierparticles being thrown outward of the whirling body and graduallysinking to the bottom,

the lighter dust going to the center and flowing upwardmaterial butpasses all other material particles to the succeeding rotary sieve orscreen through the next noz zle 55 so that the next increment ofcoarseness isremoved, the process continuing through the lastfscreenor,sieve. Material sifted or screened outby each screen falls under theaction of gravity into the chamber or compartment ahead of such screen.and is removed. from time to time or as desired. If, preferred, astation ry brush equipped. vane maybe employed tov assist gra t'yf inremoving the screenings from the s'creen surfa'ce, The last compartment,i. e. that one which is next adjacent to outlet conduit 57, may serve,substantially the 'saime purpose as the separator C, the fine dustflowing through. the pump or blower tocollector E. f

Many other variations and modifications may be de: vised and substantialchanges in constructions, and ar rangements may be employedwithout.departingfrom the principles and other fundamentals of the.process,system and apparatuses disclosedherein. Consequently'fl desire to belimited only by theinventionspirit and the. scope ofthe appendedclaims.l

I claim:

l. A flour sifting, apparatus, comprising, ahousing hav ingan inlet andan. outlet and adapted to'be interposedin an airy suction conduitbetween a. source of comminuted material and a pump for drawing materialfrorn said out; let, a. plurality of rotatablev but nonvibratingscreeens of successively finer. mesh in the, direction of flow spanningsaid housing across the path of. material flowing, from said inlet tosaid outlet, a downwardly and outwardly directed discharge chute forscreenings leading out of said housing from the upstream surface of eachscreen, wiper means for directing screenings from said upstream surfacesinto said chutes, and means for; eliecting, rotation of said screens.

2. A flour sifting apparatus comprising, a housing having an inlet andan outlet and adapted to be interposed in an air suction conduit betweena source of comminuted material and means for creating a suction forceat said outlet, a plurality of screens disposed in and transversely ofsaid housing, a downwardly inclined screenings chute leading to theexterior of said housing from each of said screens, a pair of valvemembers hingedly mounted in spaced relation to one another in each ofsaid chutes and normally urged to close the respective chute against theinflow of air from the exterior into said housing, said valve membersbeing adapted to be successively opened by the accumulation of apredetermined quantity of screenings inwardly thereof, a screen-sweepingmeans associated with the upstream surface of each screen for relativemovement over the surface thereof for sweeping the screenings therefrominto said chutes, and means including a shaft extending into saidhousing for eifecting relative rotation between said screen-sweepingmeans and the respective screens.

3. In a system of flour milling, a grinder mechanism having an inlet andan outlet for grinding material to be made into flour, a separatorincluding a chamber having an inlet connected with the outlet from saidgrinder and an outlet therefrom, a plurality of successively finerscreens arranged in spaced relation to one another within said chamberand across the flow path of material flowing from the chamber inlet tothe outlet thereof, means for removing from the receiving side of eachscreen the material retained by such screen, a settling chamber havingan inlet connected with said outlet from said separator chamber, and ablower having an inlet connected with said settling chamber outlet andhaving a discharge outlet, whereby material flow will be established ina path from said grinder through said separator and settling chamber tosaid blower in succession.

4. In a system of flour milling, a grinder mechanism having an inlet andan outlet for grinding material to be made into flour, a separatorincluding a chamber having an inlet connected with the outlet from saidgrinder and an outlet therefrom, a plurality of successively finerscreens arranged in spaced relation to one another within said chamberand across the flow path of material flowing from the chamber inlet tothe outlet thereof, means for removing from the receiving side of eachscreen the mate rial retained by such screen, a settling chamber havingan inlet connected with said outlet from said separator chamber, ablower having an inlet connected with said settling chamber outlet andhaving a discharge outlet, whereby material flow will be established ina continuous path from said grinder through said separator and settlingchamber to said blower in succession, and a porous walled collectorconnected with the outlet from said blower for receiving material dustdischarged to said blower from said settling chamber.

5. In a system of flour milling, a grinder mechanism having an inlet andan outlet for grinding material to be made into flour, a separatorincluding a chamber having an inlet connected with the outlet from saidgrinder and an outlet therefrom, a plurality of successively finerscreens arranged in spaced relation to one another within said chamberand across the flow path of material flowing from the chamber inlet tothe outlet thereof, wiper means for removing from the receiving side ofeach screen the material retained by such screen, means for effectingrelative movement between said screens and wiper means, a settlingchamber having an inlet connected with said outlet from said separatorchamber, and a blower having an inlet connected with said settlingchamber outlet and having a discharge outlet, whereby material flow willbe established in a path from said grinder through said separator andsettling chamber to said blower in succession.

6. In a system of flour milling, a grinder mechanism having an inlet andan outlet for grinding material to be made into flour, a separatorincluding a chamber having an inlet connected with the outlet from saidgrinder and an outlet therefrom, a plurality of successively finerscreens arranged in spaced relation to one another within said chamberand across the flow path of material flowing from the chamber inlet tothe outlet thereof, means for removing from the receiving side of eachscreen material retained by such screen, a settling chamber having aninlet connected with said outlet from said separator chamber, and ablower having an inlet connected with said settling chamber outlet andhaving a discharge outlet, whereby material flow will be established ina path from said grinder through said separator and settling chamber tosaid blower in succession, the connections between said grinder andseparator and between said separator and said settling chamber being ofrestricted crosssection relative to the area of any of said screenswhereby to maintain a high velocity flow of material to and from saidseparator relative to the velocity of flow through said screens.

References Cited in the file of this patent UNlTED STATES PATENTS 19,892Woodward Apr. 6, 1858 236,844 Russell Jan. 18, 1881 257,252 Strasser May2, 1882 284,488 Russell Sept .4, 1883 349,229 Lord Sept. 14, 1886465,543 Shelley Dec. 22, 1891. 739,231 Snee Sept. 15, 1903 852,558Heisel May 7, 1907 1,116,777 Williams Nov. 10, 1914 1,432,921 SwansonOct. 24, 1922 1,530,193 Montgomery Mar. 17, 1925 1,560,910 I-launam Nov.10, 1925 1,571,518 Foster Feb. 2, 1926 1,708,195 Stebbins Apr. 9, 19291,766,941 Prouty June 24, 1930 2,001,184 Cuppy May 14, 1935 2,144,418Schramm Jan. 17, 1939 2,628,786 Piperoux Feb. 17, 1953 FOREIGN PATENTS11,126 Great Britain of 1906 13,507 Great Britain June 17, 1899

